Chute for conveying molten glass



Feb. 17, 1959 K. CONRAD 2,873,555

CHUTE FOR CONVEYING MOLTEN GLASS Filed Jan. 2'?. 1954 woe/whom KEITH CONRAD @www United States Patent p Y 2,873,555' CHUTE ron CONVEYING MoLTEN GLASS Keith Conrad, Toledo, Ohio, assignor `to Owens-Illinois Glass Company, a corporation of Ohio;

i This inventionv relates to the manufacture of' glassl ar;

iilller such asgraphite. Such a coating and method of ticles from charges of molten glass and more particularly to apparatusfor conveying molten glass. p

In one method of glass manufacture, gobs 4or charges of molten glass Aare severed from a supply body of molten glass and are conveyedby free fall over chutes to molds or other apparatus for forming the glass articles. Important considerations are involved in conveying the gob or charge from the body of glass to the mold or other forming mechanism. First, the time interval of travel must be Constantin order to insure eicient and uniform operation.

the article must not be chilled or contaminated.

If the chutesfor conveying the glass are plain metal or other untreated material, the hot gob of glass has a tendency to become adhered thereto resulting in either a failure to travel to the mold or a distortion in the shape of the gob. As a result it has been common practice to lubricate the chute by either intermittent or continuous application of oil or an oil-base dope. Such a treatment of the chute facilitates the passage of the glass but it is only temporary and necessitates frequent or continuous application of the oil or oil dope. In spite of such continued application, the time of travel of the gob of glass is extremely erratic and not constant. In addition, the oil has a tendency to form a carbonaceous deposit on the gob which remains in the finished article. Also the great variation in lubrication causes the gob to become scratched or marred producing scars or imperfections in the finished article. Finally, the oil and water which are always present in the vicinity of glass forming apparatus tend to further complicate the problem of lubrication by forming on the surface of the chute and adversely affecting the lubricating action.

I have determined that a satisfactory coating for chutes should have the following requirements. First, the fric tional drag must be reduced to a minimum so that the travel of the gob is fast and constant, and the shape of the gob is not altered. Second, the coating must be hard and abrasion resistant in order not to contaminate the surface of the gob and in order not to be worn off the chute rapidly. Third, the coating must be resistant to heat. Fourth, the coating must be resistant to oil and water which are inherently present in the vicinity of the apparatus.

It is therefore an object of this invention to provide a coating for the chutes which obviates the difficulties inherent in an oil dope and in addition fulfills these requirements.

The accompanying drawing is a part sectional elevational view of an apparatus in which the invention may be embodied and employed.

Referring to the drawing, molten glass 10 is shown in a feeder 11. The feeder 11 is ofconventional construction and is provided with a plunger 12 reciprocable in opening 13 to form gobs or charges 14 of molten glass.

Second, the shape ofthe gob must not be altered during thentravel since sucht alteration maycause distortion in the finished article. Third, the surface of 2,87 3,555 Pat-eared" Feb. 17, 1959 ice 2 These gobs are severed from the body of glass by shears 15. The severed gobs fall freely and are guided by a chute 16 to funnel 17 which in turn directs the gobs to molds 18. The chute 16 may consist of several sections 19, 20 and 21. A`

Each of the sections 19, 20 and 21 of the chute 16 is provided with a heat-resistant coating 22 having the cornposition and made inl accordance with my invention.

It has heretofore been suggested that Va coating having the desired properties comprises a phenolic resin and a conveying 4molten glass is disclosed in Smith U. S. Patent 2,758,421, over which the present invention is an improvement.

My invention relates to a further improvement in coatingsfor conveying chutes. I havey determined that a coating having improved properties comprises sulfur, phenolic resin, and a iiller such as graphite. `The combination ofthe ingredients may be varied within wide limits` to provide the exact results desired, but I have determined that the coating should preferably contain not more than approximately 50% sulfur and at least 10% graphite. p

In applying the heat-resistant coating 22 to the chute, the `chute is iirst thoroughly cleaned by solvents, grit blasting orl in any other suitable manner. Sulfur, thermojsetting resin and 'graphite are intimately mixed .with a thinner and th'e mixture is' 'th'en applied to the chute by painting, spraying or dipping. The coated chute is then baked to volatilize the thinner, cure the resin and bond it to the chute. A heavy coating or successive coatings may be applied; the thicker the coating, the longer the life of the coating.

The following examples are representative of coating compositions which have given satisfactory results:

Ihe following is a specific example of the application of the coating:

(1) Crush 26 oz. sulfur to a line powder.

(2) Add 13 oz. graphite.

(3) Add l qt. (2l/z lbs.) phenolic resin having 69% solids and a curing temperature of about 250 F.

(4) Add approximately 1 qt. thinner.

(5 Paint on cleaned metal chutes.

(6) Bake at 250 F. for one hour.

(7) Repeat steps 5 and 6 to build up desired thickness of coating.

(8) Bake last coat 8 hours at 250 F.

In applying the coating care should be exercised in order that the sulfur will not be heated to excessively high temperatures.

Among the coatings which I have tested, the coats having a composition of 40% sulfur, 50% phenolic resin and 10% graphite, and 40% sulfur, 40% phenolic resin and 20% graphite, have given the best results from the standpoint of uniform and constant travel of the charge of glass combined with long life of the coating; for example, a coating of the latter formulation endured continuous operating conditions for a period of six days, in contrast to other coatings which last only about one day.

Results'of extensive 'tests on coatingsfoffnyfcomposition show that thel chutes coated as described oler distinct advantages not heretofore obtained. For example, the time of travel is uniform and constant as contrasted to bare chutes or chutes swabbed -with oil or oil dope. The -frictional drag is decreased to a minimum 'so ythat the shape or surfaceofthefgob'is notaltered. `The coating doesvnot contaminate'the. surfaceof'the gob, and is resistant toheat. Oil and Water do not alectthey coating. The coating made in accordance with thisinvention thus possesses all ythe vdesired properties f such. a coating.

Results of 'experimentation with chutesihaving coatings of my preferred'compositionsalso vshow that .the charge ofglass vrnoves down the chute atfgreaterfspeed of travel 'than onfchntesl having coatings of resinan'd graphite, andiafmuchgreater speeds f travelfthanon oh'utes s'wabbe'd with -Joil 'or foil'. dope. ',Thisfis especially of value in present 4day ydevelopment of highispe'edfglas'smaking machines where one limitation has 'been "tle speedj'oftra'vel of thegoh tothe machine. n

l/IdicationsV r'nay" be resorted toy within thesgpirit:` and scope Aof the'appended claims.

1. Apparatus "for receiving v'arid delivering a 4gob fof molten glass'which comprises a chutestructur having an 'suracef aco'ating 'consisting.essentiallyrof-anfintlrnate ture containing from 40% to 50% by weight phenolic -resin, the remainder of said vmixture consisting of comglass; `a gob .chute :mounted beneath-:the feeder in eposition for receiving gobsotmoltemglass as they are delivered from the `feeder,`said'chute'having a downwardly inclined guiding surface along which the molten gobs are guided, the chute comprising a coating bonded thereto and forming theguiding surface, said'coating consisting a graphite, and 'not lessthan,10%*byweightnor"more-'than inclined. glass=guiding surface, andkheat-bonde'd -toV said v surface a coating consisting essentially of anintmate mixture of a thermo-setting resin, graphite, and not less' than `10%by weight nor more'than 50% by weight ofs'ulphur.

`2. vApparatus for receivingiand 'delivering a vgob f I molten glass whichcomprises a' chute structure having' an inc1ine`dg`]a'ss. guiding surface, and heat-bonded'tosaid 50% :by weight of"sulphur. ,'Rferences Cited.- in thefleof thispatent UNITED l STATES PATENTS 1,199,108 vPellet' '."Sept 26,1916 L2,106,545 rBates i- ....Janf'25/1938 12,703,768 Ha'll i Mar. 8, 1.1955 ""2 ,`75-8,421 "Smith "Aug, 1:4, 1956 FOREIGN PATENTS 270;27 1 `Great lBritain 1928 

1. APPARATUS FOR RECEIVING AND DELIVERING A GOB OF MOLTEN GLASS WHICH COMPRISE A CHUTE STRUCTURE HAVING AN INCLINED GLASS GUIDING SURFACE, AND HEAT-BONDED TO SAID SURFACE A COATING CONSISTING ESSENTIALLY OF AN INTIMATE MIXTURE OF A THERMO-SETTING RESIN, GRAPHITE, AND NOT LESS THAN 10% BY WEIGHT NOR MORE THAN 50% BY WEIGHT OF SULPHUR. 